To improve the quality of wireless transmissions, communication systems often employ multiple radiating antenna elements at the transmitter to communicate information to a receiver. The receiver may then have one or more receiver antennas. Multiple antennas are desirable, as wireless communication systems tend to be interference-limited, and the use of multiple antenna elements reduces inter-symbol and co-channel interference introduced during modulation and transmission of radio signals, enhancing the quality of communications. The modeling, and thus design, of such a system, involves estimating several parameters of the space-time channel or link between the transmitter and receiver.
The number of estimated channel parameters per transmit-receiver antenna pair is multiplied by the number of permutations of transmitter-receiver antenna pairs, creating increasingly complicated calculations and decreasing estimation quality. Therefore, it is desirable to have methods of channel estimation that use a reduced set of parameters. Similarly, there is a need for an improved method of channel estimation for radio communications systems having multiple transmitter antennas.